Co-located gimbal-based dual stage actuation disk drive suspensions with motor stiffener

ABSTRACT

Various embodiments concern a gimbaled flexure having a dual stage actuation structure. The flexure comprises a gimbal which includes a pair of spring arms, a pair of struts, and a tongue between the spring arms. A motor is mounted on the gimbal. The motor comprises a top side and a bottom side opposite the top side. The bottom side of the motor faces the flexure. A stiffener is mounted on the top side of the motor. At least one layer of adhesive is located between the stiffener and the motor and bonded to the stiffener and the motor. The gimbaled flexure includes a slider mounting for attaching a slider, such as to the tongue. The motor bends the struts to move the slider mounting about a tracking axis while the stiffener limits the degree of bending of the motor.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.61/738,167, filed Dec. 17, 2012, which is herein incorporated byreference in its entirety and for all purposes.

TECHNICAL FIELD

The present invention relates to disk drives and suspensions for diskdrives. In particular, the invention is a dual stage actuation (DSA)suspension having a motor with a stiffener mounted thereon.

BACKGROUND

Dual stage actuation (DSA) disk drive head suspensions and disk drivesincorporating DSA suspensions are generally known and commerciallyavailable. For example, DSA suspensions having an actuation structure onthe baseplate or other mounting portion of the suspension, i.e.,proximal to the spring or hinge region of the suspension, are describedin the Okawara U.S. Patent Publication No. 2010/0067151, the Shum U.S.Patent Publication No. 2012/0002329, the Fuchino U.S. Patent PublicationNo. 2011/0242708 and the Imamura U.S. Pat. No. 5,764,444. DSAsuspensions having actuation structures located on the loadbeam orgimbal portions of the suspension, i.e., distal to the spring or hingeregion, are also known and disclosed, for example, in the Jurgenson U.S.Pat. No. 5,657,188, the Krinke U.S. Pat. No. 7,256,968 and the Yao U.S.Patent Publication No. 2008/0144225. Co-located gimbal-based DSAsuspensions are disclosed in co-pending U.S. Provisional ApplicationNos. 61/700,972 and 61/711,988. All of the above-identified patents andpatent applications are incorporated herein by reference in theirentirety and for all purposes.

There remains a continuing need for improved DSA suspensions. DSAsuspensions with enhanced performance capabilities are desired. Thesuspensions should be capable of being efficiently manufactured.

SUMMARY

Various embodiments concern a gimbaled flexure having a dual stageactuation structure comprising flexure. The gimbaled flexure comprisesat least one spring arm and a tongue connected to the at least onespring arm. A motor is mounted on the gimbal. The motor comprises a topside and a bottom side opposite the top side. The bottom side of themotor faces the flexure. A stiffener is mounted on the top side of themotor. The stiffener can be stiffer than a portion of the gimbal onwhich the motor is mounted. The stiffener limits the degree of bendingof the motor during activation of the motor. The stiffener cancounteract the mechanical bending influence of the portion of the gimbalon which the motor is mounted. The stiffener can be asymmetric tobalance and specifically configure bending characteristics.

Various embodiments concern a gimbaled flexure having a dual stageactuation structure. The flexure comprises a gimbal which includes apair of spring arms, a pair of struts, and a tongue between the springarms. A motor is mounted on the gimbal. The motor comprises a top sideand a bottom side opposite the top side. The bottom side of the motorfaces the flexure. A stiffener is mounted on the top side of the motor.At least one layer of adhesive is located between the stiffener and themotor and bonded to the stiffener and the motor. The gimbaled flexureincludes a slider mounting for attaching a slider, such as to thetongue. The motor bends the struts to move the slider mounting about atracking axis while the stiffener limits the degree of bending of themotor.

Further features and modifications of the various embodiments arefurther discussed herein and shown in the drawings. While multipleembodiments are disclosed, still other embodiments of the presentdisclosure will become apparent to those skilled in the art from thefollowing detailed description, which shows and describes illustrativeembodiments of this disclosure. Accordingly, the drawings and detaileddescription are to be regarded as illustrative in nature and notrestrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of the loadbeam side of a suspension havinga flexure with a dual stage actuation (DSA) structure.

FIG. 2 is an isometric view of the loadbeam side of the distal end ofthe suspension shown in FIG. 1.

FIG. 3 is an isometric view of the flexure side (i.e., the side oppositethat shown in FIG. 2) of the distal end of the suspension shown in FIG.1.

FIG. 4A is an isometric view of the stainless steel side of the flexureshown in FIG. 1.

FIG. 4B is the view of FIG. 4A but with the piezoelectric motor removed.

FIG. 5A is an isometric view of the trace side (i.e., the side oppositethat shown in FIG. 4A) of the flexure shown in FIG. 1.

FIG. 5B is the view of FIG. 5A but with the head slider removed.

FIG. 5C is the view of FIG. 5B but with the polyimide coverlay removed.

FIG. 5D is the view of FIG. 5C but with the conductive material layerremoved.

FIG. 5E is the view of FIG. 5D but with the dielectric material layerremoved.

FIG. 5F is the view of FIG. 5E but with the piezoelectric motor removed.

FIG. 6 is a side view of the distal end of the suspension shown in FIG.1.

FIG. 7 is a closer view of the portion of FIG. 6 showing the dimple,motor, and head slider.

FIGS. 8A-8C are plan views of the stainless steel side of the flexureshown in FIG. 1, illustrating the operation of the DSA structure.

FIG. 9 is an isometric view of the loadbeam side of a suspension havinga flexure with a dual stage actuation (DSA) structure.

FIG. 10 is an isometric view of the loadbeam side of the distal end ofthe suspension shown in FIG. 9.

FIG. 11 is an isometric view of the flexure side (i.e., the sideopposite that shown in FIG. 10) of the distal end of the suspensionshown in FIG. 9.

FIG. 12 is an isometric view of the stainless steel side of the flexureshown in FIG. 9.

FIG. 13A is an isometric view of the trace side (i.e., the side oppositethat shown in FIG. 12) of the flexure shown in FIG. 9.

FIG. 13B is the view of FIG. 13A but with the head slider removed.

FIG. 13C is the view of FIG. 13B but with the motor removed.

FIG. 13D is the view g of FIG. 13C but with the coverlay removed.

FIG. 13E is the view of FIG. 13D but with the conductive material layerremoved.

FIG. 13F is the view of FIG. 13E but with the dielectric material layerremoved.

FIG. 14 is a side view of the distal end of the suspension shown in FIG.9.

FIG. 15 is a closer view of the portion of FIG. 14 showing the dimple,motor, and head slider.

FIGS. 16A ₁, 16B₁, and 16C₁ are plan views of the stainless steel sideof the flexure shown in FIG. 9.

FIGS. 16A ₂, 16B₂, and 16C₂ are plan views of the trace side of theflexure shown in FIGS. 16A ₁, 16B₁, and 16C₁, respectively.

FIG. 17 is an isometric view of a tri-stage actuated suspension.

FIG. 18 is an isometric view of the stainless steel side of the distalend of a flexure having a DSA structure with a stiffener.

FIG. 19 is a side view of the distal end of the flexure shown in FIG.18.

FIG. 20 is an illustration of the flexure shown in FIG. 18 when themotor is actuated into an expanded state.

FIG. 21 is an illustration of the flexure shown in FIG. 18 when themotor is actuated into a contracted state.

FIG. 22 is an isometric view of the stainless steel side of the distalend of a flexure having a DSA structure with an asymmetric stiffener.

FIG. 23 is an illustration of the flexure shown in FIG. 22 when themotor is actuated into a contracted state.

FIG. 24 is an illustration of the flexure shown in FIG. 22 when themotor is actuated into an expanded state.

FIG. 25 is an isometric view of the stainless steel side of the distalend of a flexure having a DSA structure with a stiffener and multipleadhesives.

FIG. 26 is a distal end view of the flexure shown in FIG. 25.

FIG. 27 is an illustration of the flexure shown in FIG. 25 when themotor is actuated into an expanded state.

FIG. 28 is an isometric view of the stainless steel side of the distalend of a flexure having a DSA structure with a multiple thicknessstiffener attached to the motor with multiple adhesives.

FIG. 29 is a detailed side view of the distal end of the flexure shownin FIG. 28.

FIG. 30 is an isometric view of the stainless steel side of the distalend of a flexure having a DSA structure with an asymmetric stiffenerattached to the motor with multiple adhesives.

FIG. 31 is an isometric view of the stainless steel side of the distalend of a flexure having a DSA structure with an asymmetric stiffener.

FIGS. 32A and 32B are illustrations of the flexure shown in FIG. 31 whenthe motor is actuated into contracted and expanded states, respectively.

DESCRIPTION OF THE INVENTION

FIG. 1 is an isometric view of the loadbeam side of a suspension 10having a flexure 12 with a co-located or gimbal-based dual stageactuation (DSA) structure 14 in accordance with a first embodiment ofthis disclosure (i.e., a stainless steel side version). FIG. 2 is adetailed isometric view of the distal end of the suspension 10. FIG. 3is a detailed isometric view of the flexure side of the distal end ofthe suspension 10, which shows the side opposite that shown in FIG. 2.As shown in FIG. 1, the suspension 10 includes a baseplate 16 as aproximal mounting structure. As further shown in FIG. 1, the suspension10 includes a loadbeam 18 having a rigid or beam region 20 coupled tothe baseplate 16 along a spring or hinge region 22. The loadbeam 18 canbe formed from stainless steel.

Flexure 12 includes a gimbal 24 at the distal end of the flexure 12. ADSA structure 14 is located on the gimbal 24, adjacent the distal end ofthe loadbeam 18. As best shown in FIG. 2, the suspension 10 includes agimbal limiter 26 comprising a tab 28 configured to engage a stopportion 30 of the loadbeam 18. A head slider 32 is mounted to a slidermounting or tongue 33 of the gimbal 24, on the side of the suspension 10that is opposite the loadbeam 18. DSA structure 14 includes a motor 34,which is a PZT or other piezoelectric actuator in the illustratedembodiment, mounted to the gimbal 24 of the flexure 12 between theloadbeam 18 and the head slider 32. As described in greater detailbelow, in response to electrical drive signals applied to the motor 34,the motor drives portions of the gimbal 24, including the tongue 33 andslider 32, about a generally transverse tracking axis. Proximal anddistal, as used herein, refers to the relative direction along thelongitudinal axis of the suspension while lateral refers to the leftand/or right directions orthogonal to the longitudinal axis of thesuspension. For example, the baseplate 16 is proximal of the loadbeam 18while opposite ends of the motor 34 extend laterally.

FIGS. 4A and 4B are isometric views of the stainless steel side of theflexure 12 and DSA structure 14 shown in FIG. 1. The motor 34 is notshown in FIG. 4B to show further details of the tongue 33. FIGS. 5A-5Fare isometric views of the trace side (i.e., the side opposite thatshown in FIGS. 4A and 4B) of the flexure 12 and DSA structure 14.Specifically, FIGS. 5A-5F show the various layers that comprise theflexure 12 and DSA structure 14. FIG. 5B is the drawing of FIG. 5A butwith the head slider 32 removed to further show details of the tongue33. FIG. 5C is the drawing of FIG. 5B but with a polyimide coverlay 46removed to reveal a conductive material layer 44 including traces 60 andother structures formed in the conductive material layer that isotherwise underneath the polyimide coverlay 46. FIG. 5D is the drawingof FIG. 5C but with the conductive material layer 44 removed to morefully reveal the dielectric layer 42 that is otherwise underneath theconductive material layer 44. FIG. 5E is the drawing of FIG. 5D but withthe dielectric layer 42 removed to show only the stainless steel layer40 and the motor 34. FIG. 5F is the drawing of FIG. 5E but with themotor 34 removed to illustrate only the stainless steel layer 40 of theflexure 12. It will be understood that the stainless steel layer 40could alternatively be formed from another metal or rigid material.

As shown in FIGS. 5A-5F, the flexure 12 is formed from overlaying springmetal such as stainless steel layer 40, polyimide or other dielectriclayer 42, copper or other conductive material layer 44 and polyimidecoverlay 46. The dielectric layer 42 generally electrically isolatesstructures formed in the conductive material layer 44 from adjacentportions of the stainless steel layer 40. Coverlay 46 generally coversand protects the structures formed in the conductive material layer 44.The gimbal 24 includes the spring arms 52 and the tongue 33. The springarms 52 extend from the base portion 50. The mounting portion 54, whichis part of the tongue 33, is supported between the spring arms 52 by apair of struts 56 that extend from support regions 58 on the distal endportions of the spring arms 52. In some embodiments, the pair of struts56 is the only part of the stainless steel layer 40 that connects orotherwise supports the tongue 33 between the spring arms 52.Specifically, the struts 56 can be the only structural linkage betweenthe spring arms 52 and the tongue 33. Also, the struts 56, in connectingwith the tongue 33, can be the only part of the stainless steel layer 40that connects between the spring arms 52 distal of the base portion 50.As shown, the struts 56 are offset from one another with respect to thelongitudinal axis of the flexure 12 or otherwise configured so as toprovide for rotational movement of the mounting portion 54 about thetracking axis with respect to the spring arms 52. As best shown in FIG.8B (further discussed herein), one strut 56 of the pair of struts 56 islocated proximally of the motor 34 while the other strut 56 of the pairof struts 56 is located distally of the motor 34 such that the motor 34is between the pair of struts 56. Each strut 56 has a longitudinal axisthat extends generally perpendicular with respect to the longitudinalaxis of the suspension 10. The longitudinal axes of the struts 56 extendparallel but do not intersect or otherwise overlap with each other whenthe struts 56 are not stressed (e.g., not bent). As shown in FIG. 5F,the struts 56 can each be the narrowest part of the stainless steellayer 40 in an X-Y plane (as viewed from the overhead perspective ofFIG. 8B) while the thickness of the stainless steel layer 40 can beconsistent along the flexure 12.

As perhaps best shown in FIGS. 4A and 5E, the opposite ends of the motor34 are attached (e.g., by structural adhesive such as epoxy) to thesupport regions 58 of the spring arms 52. In this way, the supportregions 58 can serve as motor mounting pads. Portions of the dielectriclayer 42 extend underneath the struts 56 in FIG. 4B. As shown in FIG.5C, a plurality of traces 60 formed in the conductive material layer 44extend between the base portion 50 and the tongue 33 over supportingportions 62 formed in the dielectric layer 42. A number of the traces 60terminate at locations on a distal region on the tongue 33 and areconfigured to be electrically attached to terminals of the read/writehead (not shown) on the slider 32. Other traces 60 terminate at acontact such as copper pad 64 on the tongue 33, below the motor 34. Inthe illustrated embodiment, the copper pad 64 is located generallycentrally between the spring arms 52. As perhaps best shown in FIG. 4B,the dielectric layer 42 has an opening over the pad 64. A structural andelectrical connection, e.g., using conductive adhesive, is made betweenthe copper pad 64 and an electrical terminal on the motor 34. Anotherelectrical connection to a terminal on the motor 34 (e.g., a groundterminal) is made through the dimple 36 (i.e., the dimple 36 is inelectrical contact with the terminal on the motor 34). In otherembodiments, the electrical connections to the motor 34 can be made byother approaches and structures.

As shown in FIGS. 5A and 5B, the slider 32 sits on the coverlay 46 ofthe tongue 33. Coverlay 46 provides protection for the traces 60. Asshown in FIGS. 5A-5C, which show that the supporting portions 62 areoffset with respect to the longitudinal direction of the flexure 12,portions of the traces 60 on the opposite sides of the flexure 12 areoffset from each other in a manner similar to that of the struts 56(e.g., portions of the traces overlay the struts in the illustratedembodiment). Offset traces of this type can increase the strokeperformance of the DSA structure 14. Various other embodiments (notshown) do not have offset traces. It is noted that, in some embodiments,the supporting portions 62 may provide negligible mechanical support tothe tongue 33 relative to the struts 56.

FIGS. 6 and 7 are side views of the suspension 10, illustrating thegimbal 24 and DSA structure 14. As shown, the dimple 36, which is astructure formed in the stainless steel material that forms the loadbeam18, and which extends from the loadbeam 18, engages the motor 34 andfunctions as a load point by urging the portion of the gimbal 24 towhich the motor 34 is connected out of plane with respect to the baseportion 50 of the flexure 12. A bend or transition in the flexure 12 canoccur at any desired location along the spring arms 52 due to the urgingof the gimbal 24 by the dimple 36. The dimple 36 can also provide anelectrical contact to a terminal (not visible) on the portion of themotor 34 engaged by the dimple. For example, if the stainless steelloadbeam 18 is electrically grounded or otherwise part of an electricalcircuit, the dimple 36 can provide an electrical ground potential orelectrical connection to the terminal on the motor 34. Various otherembodiments (not shown) include other dimple structures such as platedstructures that provide these functions. The dimple 36 can be platedwith conductive material such as gold to enhance the electricalconnection to the terminal of the motor 34 which can also be plated withconductive material such as gold. Still other embodiments (not shown)use structures other than the dimple 36 to provide a grounding or otherelectrical connection to the motor 34. In one such embodiment, forexample, there is another copper pad on the end of one of the supportregions 58, and an electrical connection (e.g., a ground connection) canbe made by a structure such as conductive adhesive between a terminal onthe motor 34 and the conductive material pad on the support region ofthe flexure 12. In some embodiments, the motor 34 is structurallyattached to the tongue 33 at a location between the opposite lateral endportions of the tongue 33. In such embodiments, the motor 34 is attachedto the tongue 33 of the gimbal 24 in addition to the motor 34 beingattached to the support regions 58 of the spring arms 52.

The operation of DSA structure 14 can be described with reference toFIGS. 8A-8C that are plan views of the stainless steel side of thegimbal 24 of the flexure 12. As shown in FIG. 8B, the DSA structure 14and tongue 33 are in a neutral, undriven state with the tongue 33generally centrally located between the spring arms 52 when no trackingdrive signal is applied to the motor 34. As shown in FIG. 8A, when afirst potential (e.g., positive) tracking drive signal is applied to themotor 34, the shape of the motor changes and its length generallyexpands. This change in shape increases the distance between the supportregions 58 as shown in FIG. 8A, which in connection with the mechanicalaction of the linking struts 56, causes the tongue 33 to move or rotatein a first direction with respect to the spring arms 52 about thetracking axis. As shown, the lengthening of the motor 34 stretches thegimbal 24 laterally and causes the struts 56 to bend (e.g., bow inward).Because of the offset arrangement of the struts 56, the struts 56 bendsuch that the tongue 33 rotates in the first direction.

As shown in FIG. 8C, when a second potential (e.g., negative) trackingdrive signal is applied to the motor 34, the shape of the motor changesand its length generally contracts. This change in shape decreases thedistance between the support regions 58 as shown in FIG. 8C, which inconnection with the mechanical action of the linking struts 56, causesthe tongue 33 to move or rotate in a second direction with respect tothe spring arms 52 about the tracking axis. The second direction isopposite the first direction. As shown, the shortening of the motor 34compresses the gimbal 24 laterally and causes the struts 56 to bend(e.g., bow outward). Because of the offset arrangement of the struts 56,the struts 56 bend such that the tongue 33 rotates in the seconddirection. Some, although relatively little, out-of-plane motion ofother portions of the gimbal 24 is produced during the tracking actionof DSA structure 14 as described above. With this embodiment of thisdisclosure, slider mounting on the tongue 33 generally rotates withrespect to the spring arms 52 as the spring arms 52 stay stationary orexperience little movement.

FIG. 9 is an isometric view of the loadbeam-side of a suspension 110having a flexure 112 with a co-located or gimbal-based dual stageactuation (DSA) structure 114 in accordance with a second embodiment ofthis disclosure (i.e., a trace side version). The components of thesuspension 110 can be configured similarly to the previously discussedsuspension 10 unless otherwise described or illustrated. FIG. 10 is anisometric view of the distal end of the suspension 110. FIG. 11 is anisometric view of the flexure-side of the distal end of the suspension110, showing the side opposite that shown in FIG. 10. As shown in FIG.10, the suspension 110 includes a baseplate 116 as a proximal mountingstructure. As further shown in FIG. 11, the suspension 110 includes aloadbeam 118 having a rigid or beam region 20 coupled to the baseplate116 along a spring or hinge region 122. The loadbeam 18 can be formedfrom stainless steel. Flexure 112 includes a gimbal 124 at its distalend. A DSA structure 114 is located on the gimbal 124, adjacent thedistal end of the loadbeam 118. The illustrated embodiment of thesuspension 110 also includes a gimbal limiter 126 comprising a tab 128configured to engage a stop portion 130 of the loadbeam 118. The DSAstructure 114 includes a motor 134, which is a PZT actuator in theillustrated embodiment, mounted to a motor mounting region of the tongue133, on the side of the flexure 112 opposite the loadbeam 118. A headslider 132 is mounted to the side of the motor 134 opposite the flexure112. As described in greater detail below, in response to electricaldrive signals applied to the motor 134, the motor drives portions of thegimbal 124, including portions of the tongue 133, motor 134 and slider132, about a generally transverse tracking axis.

FIG. 12 is a detailed isometric view of the stainless steel-side of theflexure 112 and DSA structure 14 shown in FIG. 9. FIGS. 13A-13F areisometric views of the flexure 112 and DSA structure 114 showing theside opposite that shown in FIG. 12. Specifically, FIGS. 13A-13F showthe various layers that comprise the flexure 112 and DSA structure 114.FIG. 13B is the drawing of FIG. 13A but with the head slider 132 removedto further show details of the motor 134 on the tongue 133. FIG. 13C isthe drawing of FIG. 13B but with the motor 134 removed to reveal detailsof the tongue 133. FIG. 13D is the drawing of FIG. 13C but with thecoverlay 146 removed to reveal a conductive material layer 144 includingtraces 160 and other structures formed in the conductive material layer144. FIG. 13E is the drawing of FIG. 13D but with the conductivematerial layer 144 removed to further reveal the dielectric layer 142.FIG. 13F is the drawing of FIG. 13E but with the dielectric layer 142removed to show only the stainless steel layer 140 of the flexure 112.It will be understood that the stainless steel layer 140 couldalternatively be formed from another metal or rigid material. As shown,the flexure 112 is formed from overlaying spring metal such as stainlesssteel layer 140, polyimide or other dielectric layer 142, copper orother conductive material layer 144, and coverlay 146. The dielectriclayer 142 generally electrically isolates structures formed in theconductive material layer 144 from adjacent portions of the stainlesssteel layer 140. Coverlay 146 generally covers and protects thestructures formed in the conductive material layer 144.

The gimbal 124 includes spring arms 152 and the tongue 133. The baseportion 150, the spring arms 152, and the center region 154 are eachformed from the stainless steel layer 140. The spring arms 152 extendfrom the base portion 150. The center region 154, which is a center partof the tongue 133, is connected to the distal ends of the spring arms152 and is supported between the spring arms 152. Also formed in thestainless steel layer 140 is a pair of struts 153. Each of the struts153 extends from one of the opposite lateral sides of the center region154 and has a motor mounting flag or pad 155 on its outer end. As shown,the struts 153 are offset from one another with respect to thelongitudinal axis of the flexure 112 or otherwise configured so as toprovide for rotational movement of the motor 134 and the head slider 132mounted thereto about the tracking axis with respect to the centerregion 154. Each strut 153 comprises a longitudinal axis that extendsgenerally perpendicular with respect to the longitudinal axis of thesuspension 110. The longitudinal axes of the struts 153 extend parallelbut do not intersect or otherwise overlap with each other when thestruts 153 are not stressed (e.g., not bent). The struts 153 can be theonly structural linkage between the center region 154 and the pads 155(e.g., the only part of the stainless steel layer 140 connecting thecenter region 154 with the pads 155 is the struts 153, a single strut153 for each pad 155). As shown in FIG. 13F, the struts 153 can each bethe narrowest part of the stainless steel layer 140 in an X-Y plane (asviewed from the overhead perspective of FIG. 16B ₁) while the thicknessof the stainless steel layer 140 can be consistent along the flexure112.

As shown in FIG. 13D, a plurality of traces 160 are formed in theconductive material layer 144 and extend between the base portion 150and tongue 133 along paths generally laterally outside the spring arms152 and over supporting portions 162 formed in the dielectric layer 142.A number of the traces 160 terminate at locations adjacent the distalregion of the tongue 133 and are configured to be electrically attachedto read/write head terminals (not shown) on the slider 132. A pair ofpower traces 161 for powering the motor 134 are also formed in theconductive material layer 144, and extend between the base portion 150and a proximal portion of the tongue 133 along paths generally insidethe spring arms 152 and over supporting portions 163 formed in thedielectric layer 142. The motor power traces 161 terminate at a firstmotor terminal pad 167 on one of the motor mounting pads 155. A secondmotor terminal pad 169 is formed in the conductive material layer 144 onthe other motor mounting pad 155, and is coupled by a trace 171 to aconductive via 173 that is shown on the tongue 133 at a location betweenthe motor mounting pads 155. As best viewed in FIG. 13D, via 173 extendsthrough an opening 175 in the dielectric layer 142 (shown in FIG. 13E)to electrically contact the stainless steel layer 140 of the flexure112. The motor terminal pad 169 can be electrically connected to aground potential at the stainless steel layer 140 by the trace 171 andthe via 173. As shown in FIG. 12, structures such as tabs 157 in thestainless steel layer 140 are formed out of the plane of the stainlesssteel layer and engage the distal portion of the trace supportingportions 162 to push the terminal ends of the traces 161 down so theterminals on the slider 132 can be correctly electrically attached(e.g., by solder bonds) to the traces while accommodating the thicknessof the motor 134. FIG. 13E also illustrates other holes in thedielectric layer that can be used in connection with conductive vias toelectrically connect (e.g., ground) traces and other structures in theconductive material layer 144 to the stainless steel layer 140. In otherembodiments, other approaches and structures can be used to couple thetracking drive signals to the terminals on the motor 134.

The electrical terminals on the motor 134 may be on the same side (e.g.,top or bottom) but opposite longitudinal ends of the motor 134. As shownin FIGS. 13B and 13C, the motor 134 can be attached to the gimbal 124 bybonding the electrical terminals of the motor 134 to the motor terminalpads 167 and 169 using conductive adhesive. By this approach, the motor134 is both structurally and electrically connected to the gimbal 124.As shown in FIG. 13C, the motor terminal pads 167 and 169 are exposedthrough openings in the coverlay 146 to provide access for theconductive adhesive.

FIGS. 14 and 15 are side views of the suspension 110, illustrating thegimbal 124 and DSA structure 114. As shown, the dimple 136, which is astructure formed in the stainless steel of the loadbeam 118 and whichprojects from the loadbeam 118, engages the center region 154 ofstainless steel layer 140 on the side of the tongue 133 opposite themotor 134. Dimple 136 functions as a load point by urging the portion ofthe gimbal 124 to which the motor 134 is connected out of plane withrespect to the base portion 150 of the flexure 112. In the illustratedembodiment, the motor 134 is located between the tongue 133 and the headslider 132 (e.g., the motor 134 is sandwiched in a vertical axis). Asshown in FIGS. 14 and 15, the slider 132 is structurally supported bythe motor 134 such that the only structural linkage between the flexure112 and the slider 132 runs through or otherwise includes the motor 134.The manner by which the stainless steel tabs 157 locate the portion ofdielectric layer 142 with the terminal ends of the traces 160 at thecorrect z-height and adjacent to the portion of the head slider 132 thatincludes the read/write head terminals is shown in FIG. 15.

The operation of DSA structure 114 can be described with reference toFIGS. 16A ₁, 16A₂, 16B₁, 16B₂, 16C₁ and 16C₂ that are plan views of thegimbal 124 of the flexure 112. FIGS. 16A ₁, 16B₁ and 16C₁ illustrate thestainless steel side of the flexure 112, and FIGS. 16A ₂, 16B₂ and 16C₂illustrate the trace side of the flexure 112, with the motor 134 andhead slider 132 shown. As shown in FIGS. 16B ₁ and 16B₂, the DSAstructure 114 and tongue 133, as well as the motor 134 on the linkageformed by the motor mounting pads 155 and struts 153, are in a neutral,undriven state with the head slider positioned generally parallel to thelongitudinal axis of the flexure 112 when no tracking drive signal isapplied to the motor 134. The struts 153 are not bent or otherwisestressed in this state. As shown in FIGS. 16A ₁ and 16A₂, when a firstpotential (e.g., positive) tracking drive signal is applied to the motor134, the shape of the motor changes and its length generally expands.This change in shape increases the distance between the motor mountingpads 155, which in connection with the mechanical action of the linkingstruts 153, causes the motor 134, and therefore the head slider 132mounted thereto, to move or rotate in a first direction with respect tothe longitudinal axis of the flexure 112 about the tracking axis. Asshown, the lengthening of the motor 134 stretches the struts 153laterally and causes the struts 153 to bend (e.g., bow inward). Becauseof the offset arrangement of the struts 153, the struts 153 bend suchthat the motor 134 and the head slider 132 rotate in the firstdirection.

As shown in FIGS. 16C ₁ and 16C₂, when a second potential (e.g.,negative) tracking drive signal is applied to the motor 134, the shapeof the motor changes and its length generally contracts. This change inshape decreases the distance between the motor mounting pads 155, whichin connection with the mechanical action of the linkage including struts153, causes the motor 134, and therefore the head slider 132 mountedthereto, to move or rotate in a second direction with respect to thelongitudinal axis of the flexure 112 about the tracking axis. The seconddirection is opposite the first direction. As shown, the shortening ofthe motor 134 compresses the struts 153 laterally and causes the struts153 to bend (e.g., bow outward). Because of the offset arrangement ofthe struts 153, the struts 153 bend such that the motor 134 and the headslider 132 rotate in the second direction.

Some, although relatively little, out-of-plane motion of other portionsof the gimbal 124 may be produced during the tracking action of DSAstructure 114. The linkage provided by the struts 153 accommodates themotion of the motor 134 so the remaining portions of the tongue 133remain generally aligned with respect to the longitudinal axis of theflexure 112 during this tracking action. For example, the motor 134 andslider 132 rotate, but the center region 154 (or more broadly the tongue133) does not rotate or rotates only an insignificant or trivial amount.

FIG. 17 is an illustration of a suspension 210 in accordance withanother embodiment of this disclosure. As shown, the suspension 210includes a co-located or gimbal-based DSA structure 214 and a loadbeamor baseplate-type DSA structure 290. In this way, the suspension 210 isa tri-stage actuated suspension. In one embodiment, the DSA structure214 is substantially the same as the DSA structure 114 described above(e.g., is configured with any aspect described or shown in connectionwith FIGS. 9-16C ₂) except as otherwise specified or shown. In anotherembodiment, the DSA structure 214 is substantially the same as the DSAstructure 14 described above (e.g., is configured with any aspectdescribed or shown in connection with FIGS. 1-8C) except as otherwisespecified or shown. Other embodiments of suspension 210 include othergimbal-based DSA structures. The DSA structure 290 can be any known orconventional DSA structure such as any of those described above in thebackground section.

Bowing, twisting, and/or asymmetric bending can be present in varioussuspensions such as those described above. For example, returning thesuspension of FIGS. 1-8C, when the motor 34 on the suspension 10 isactuated to expand, the motor 34 can vertically deflect by bowing suchthat the lateral ends of the motor 34 move toward the slider 32 and thestainless steel layer 40 of the gimbal 24 relative to the middle of themotor 34. In other words, upon expansion, the lateral ends of the motor34 bend downward and/or the middle of the motor 34 bends upwards. Thedeflection of the motor 34 in this manner can be due to the resistanceprovided by the gimbal 24. For example, the gimbal 24, being on one sideof the motor 34 while the other side of the motor 34 is unrestrained,resists the expansion of the motor 34 and therefore causes the motor 34,along with the attached gimbal 24, to vertically deflect. Conversely,when the motor 34 is electrically activated with the opposite polarityto contract, the motor 34 can deflect by bowing in the oppositedirection such that the lateral ends of the motor 34 move away theslider 32 and the stainless steel layer 40 of the gimbal 24 relative tothe middle of the motor 34 which moves toward the slider 32 and thestainless steel layer 40. In other words, upon expansion, the lateralends of the motor 34 bend upward and/or the middle of the motor 34 bendsdownwards. The deflection of the motor 34 in this manner can likewise bedue to the resistance provided by the gimbal 24 on one side of the motor34. The vertical direction of this bending can reduce stroke efficiencyof the motor 34. For example, the motor 34 cannot fully extend orcontract along its longitudinal axis when also bending in a verticaldirection, and as such some stroking range is lost. Furthermore, themotor 34 can twist about its longitudinal axis (typically transverselyoriented on the gimbal 24) during expansion and contraction. This twistcan be due to asymmetric bending stiffness of the offset gimbal struts56. Asymmetric bending and twisting can also lead to increased gimbalmodes (natural frequencies) causing resonance performance issues.Reduced resonance performance can lead to lower servo bandwidth in thedisk drives into which the suspensions are incorporated. This, in turn,can increase the distance that the individual tracks are spaced fromeach other on the disks, and thereby reduce the overall amount of datathat can be packed onto the disk surface.

Various embodiments of this disclosure include a stiffener componentthat is bonded or otherwise attached to a side (e.g., a top or freeside) of a motor. Such a stiffener can limit the bending of the motorand/or gimbal during motor activation. FIGS. 18-32B show variousembodiments of suspensions having a stiffener mounted on a motor toaddress the issues discussed above.

FIG. 18 is an isometric view of the stainless steel side of a flexure212. FIG. 19 is a side view of the flexure 212. The flexure 212 is partof a DSA structure 214 that can be similar to that of the DSA structure14 described above or other DSA structure referenced herein except wherenoted. Features of flexure 212 that are the same or similar to those offlexure 12 are indicated by similar reference numbers. A stiffener 280is mounted on the motor 234. The stiffener 280 is attached to the motor234 by adhesive 282 disposed between the stiffener 280 and the motor234. Specifically, the adhesive 282 can be a layer of adhesive that isbonded to a bottom side of the stiffener 280 and a top side of the motor234. In the embodiment shown in FIG. 18, the stiffener 280 is locatedover the entire top or free surface of the motor 234 (i.e., the surfaceof the motor 234 that is opposite the bottom side of the motor 234 thatfaces the tongue 233). As shown, the four edges (lateral sides, front,and back) of the stiffener 280 are aligned with the four edges (lateralsides, front, and back) of the motor 234.

The stiffener 280 will generally have sufficient stiffness to at leastpartially offset the stiffness of the portion of gimbal 224 that isresisting motion of the motor 234 and causing the stroke-reducingbending. In some embodiments, the stiffener 280 is made from metal suchas stainless steel, aluminum, nickel, titanium or other structuralmetal. In various other embodiments, the stiffener 280 is formed from apolymer material. A polymer stiffener may have increased thickness (ascompared to a metal stiffener) to provide the desired bending stiffness.The stiffener 280 can, for example, be etched, cut or otherwise formedfrom sheet or film stock. In some embodiments, the stiffener 280 can beabout 10-25 μm in thickness. The stiffener can be thicker or thinner inother embodiments.

The embodiment of FIG. 18 further includes a reduced thickness region284 at the center of the stiffener 280. In this or in other ways, astiffener can have a first thickness along a first portion of thestiffener and a second thickness along a second portion of thestiffener, the second thickness less than the first thickness. Thereduced thickness region 284 can be a surface of the stiffener 280 thatis positioned and configured to make contact with a load point dimple ofthe loadbeam (not shown). Reducing the thickness of the stiffener 280 atthe dimple contact location can allow the dimple to extend into thecavity created by the reduced thickness region 284, which reduces theoverall height of the suspension 210 because the loadbeam can be closerto the flexure 212. Various other embodiments do not include the partialthickness region 284. Other configurations for a reduced thicknessregion are further discussed herein.

Adhesive 282 forms a relatively thin material layer between the motor234 and stiffener 280 (e.g., about 2-25 μm in some embodiments). In someembodiments, the adhesive 282 has a relatively low elastic modulus toenhance the operation of the DSA structure 214. Low elastic modulusadhesives 282 can provide reduced resistance of the stiffener 280 onexpansion and contraction of the motor 234, while still enhancing thebending stiffness of the DSA structure 214. Embodiments of flexure 212with adhesive 282 having an elastic modulus of about 100 MPa havedemonstrated enhanced performance. Other embodiments can have adhesive282 with a different elastic modulus.

The motor 234 is mounted on the flexure 212 by being connected to a pairof connectors 245. The connectors 245 can connect with respective anodeand cathode terminals of the motor 234. The connectors 245 can furtherconnect with respective traces running along the flexure 212 toelectrically activate the motor 234. The connectors 245 can comprisesolder, conductive epoxy (e.g., silver filled), or other material forforming an electrode connection. The connectors 245 can structurallyattach the motor 234 to the flexure 212. Specifically, the pair ofconnectors 245 can connect the lateral ends of the motor 234 to the pairof spring arms 252, respectively. The slider 232 is mounted to a slidermounting of the tongue 233. The slider mounting is a surface of thetongue 233 to which the slider 232 can be attached, such as with anadhesive such as epoxy. Rotation of the tongue 333 by actuation of themotor 234 rotates the slider mounting, and thereby the slider 332, abouta tracking axis.

FIG. 20 is an isometric view of the flexure 212 and shows an example ofa state of the flexure 212 when the motor 234 is electrically activatedto expand to an expanded state. As shown, the motor 234 bends toward thestiffener 280 (i.e., in the direction opposite of the bending inembodiments of the same flexure 212 when the motor 234 expands withoutthe stiffener 280) such that the lateral ends of the motor 234 move awayfrom the slider 232 and the stainless steel layer 240 relative to themiddle of the motor 234 which moves toward the slider 232 and thestainless steel layer 240. In other words, upon expansion whilerestrained by the stiffener 280, the lateral ends of the motor 234 bendupward while the middle of the motor 234 bends downwards, which is theopposite bending profile had the stiffener 280 not been attached to themotor 235. Conversely, FIG. 21 is the same isometric view of the flexure212 as FIG. 20 when the motor 234 is electrically activated to contract.As shown, the motor 234 bends away the stiffener 280 (i.e., in thedirection opposite of the bending in embodiments of the same flexure 212when the motor 234 contacts without the stiffener 280) such that thelateral ends of the motor 234 move toward the slider 232 and thestainless steel layer 240 relative to the middle of the motor 234 whichmoves away the slider 232 and the stainless steel layer 240. In otherwords, upon contraction while restrained by the stiffener 280, thelateral ends of the motor 234 bend downward while the middle of themotor 234 bends upwards, which is the opposite bending profile had thestiffener 280 not been attached to the motor 235. However, it is notedthat not all embodiments are so limited and that the stiffener 280 canchange the bending profile of the flexure 212 in additional oralternative ways.

It is noted that the presence of the stiffener 280 on the motor 234 canchange the amount of deflection of the motor 234 when contracted. Thisbending action is produced because the overall stiffness of thestiffener 280 and motor 234 is stronger than the stiffness of theassociated portion of the flexure 212 (e.g., the stainless steel layer240 specifically) on the other side of the motor 234 with respect to thestiffener 280. In this way, the stiffener 280 can balance or counteractthe stiffness of the flexure 212 about the motor 234 to control or limitvertical deflection. Limiting the vertical deflection increases thestroke because the motor 234 is allowed to more fully expand or contractalong an axis that pushes or pulls the areas at which the motor 234 isattached to the flexure 212 to move the tongue 233 and the slider 232.Increasing the stroke of the motor 234 increases the rotational strokeof the DSA structure 214. In some embodiments, the stiffener 280 canincrease the stroke by over 70% (e.g., over embodiments of a similarflexure without the stiffener 280). As such, the presence andconfiguration (e.g., shape, elastic modulus) of the stiffener 280 can bebalanced with the mechanics of the flexure 212 to minimize bending ofthe motor 234 and flexure 212, maximize longitudinal stroke of the motor234, and/or reverse the bending profile of the motor 234.

As shown in FIGS. 20 and 21, the low modulus adhesive 282 deforms inshear during this actuation of the motor 234. While the profile of thestiffener 280 is matched to the profile of the motor 234 when the motor234 is not activated, as shown in FIG. 18, the motor 234 extends beyondthe lateral ends of the stiffener 280 in the embodiment of FIG. 20 asthe motor 234 expands such that the respective profiles of the stiffener280 and the motor 234 no longer match. In FIG. 20, the adhesive 282 isshown stretching between the relatively larger profile of the motor 234and the relatively smaller profile of the stiffener 280. In FIG. 21, theadhesive 282 is shown stretching between the relatively smaller profileof the motor 234 and the relatively larger profile of the stiffener 280.The relatively low elastic modulus of the adhesive 282 allows theadhesive 282 to stretch to accommodate the shear force generated by thechanges between the profiles of the stiffener 280 and the motor 234. Arelatively higher modulus adhesive 282 (not shown) may not deform inshear to the extent of a lower modulus adhesive, and may thereby reducethe amount of expansion of the motor 234 to reduce the stroke increaseprovided by the stiffener 280. Performance advantages can thereby beachieved by balancing the elastic modulus of the adhesive 282 and theelastic modulus of the stiffener 280. The elastic modulus of theadhesive 282 can be approximately 2000 times lower than the modulus ofthe material that forms the stiffener 280.

During actuation, the motor 234 may twist about the longitudinal axis ofthe motor 234 during actuation of the motor 234. Also, the stiffener 280may also be caused to twist about the longitudinal axis of the stiffener280 by the actuation of the motor 234. However, the presence of thestiffener 280 can limit the degree of twisting of the motor 234 aboutthe longitudinal axis of the motor 234. In some embodiments, because thetwisting can be caused by the resistance provided by the flexure 212, asdiscussed above, the presence of the stiffener 280 on the side of themotor 234 opposite the flexure 212 can reverse the direction of twist ascompared to an embodiment without the stiffener 280. As such, thepresence and configuration (e.g., shape, elastic modulus) of thestiffener 280 can be balanced with the mechanics of the flexure 212 tominimize twisting, maximize longitudinal stroke of the motor 234, and/orreverse the twisting profile of the motor 234.

FIGS. 22-24 are illustrations of a flexure 312 having a DSA structure314 with an asymmetric stiffener 380 in accordance with anotherembodiment of this disclosure. The flexure 312 is part of a DSAstructure 314 that can be similar to that of DSA structure 214 describedabove or other DSA structure referenced herein except where noted.Features of flexure 312 that are the same or similar to those of otherflexures are indicated by similar reference numbers. The gimbal 324 isshown with the motor 334 in a neutral or unactuated state in FIG. 22, acontracted actuated state in FIG. 23, and an expanded actuated state inFIG. 24. Stiffener 380 can be attached to motor 334 by adhesive 382. Asshown, the stiffener 380 has a central section 387 and a pair of armscomprising a first arm 388 and a second arm 389. A first arm 388 extendslaterally away from the central section 387 in a first direction (i.e.to the right and orthogonal relative to the longitudinal axis of thegimbal 324, parallel relative to the longitudinal axis of the motor334). A second arm 389 extends laterally away from the central section387 in a second direction (i.e. to the right and orthogonal relative tothe longitudinal axis of the gimbal 324, parallel relative to thelongitudinal axis of the motor 334) opposite the first direction.

The stiffener 380 is asymmetric about both of the length and width axesof the central section 387. For example, the first arm 388 extends alonga first longitudinal axis, the second arm 389 extends along a secondlongitudinal axis, and the first longitudinal axis is offset from thesecond longitudinal axis. As shown, the first arm 388 is proximalrelative to the second arm 389. The offset relationship of the first arm388 and the second arm 389 can mirror the offset relationship of thestruts 356. It is noted that while strut 356 is shown in FIGS. 22-24,the configuration of the struts 356 can be the same as the struts 56shown in FIG. 4B. For example, a first strut 356 on the right side ofthe flexure 312 can be proximal of the second strut 356 on the left sideof the flexure 312 while the first arm 388 on the right side of thestiffener 380 is proximal of the second arm 389 on the left side of thestiffener 380. The stiffener 380 can be between the struts 356 (e.g.,from a plan view perspective or along a plane that is coplanar with theflexure 312). The offset profile of the first arm 388 and the second arm389 corresponding to the offset profile of the struts 356 allows thefirst arm 388 to mechanically counteract the proximal strut 356 and thesecond arm 389 to mechanically counteract the distal strut 356. In someembodiments, the width of the first arm 388 is different (e.g., less)than the width of the second arm 389. In other embodiments (not shown),the stiffener has other asymmetrical shapes or is symmetric about thecentral section 387.

The stiffener 380 can provide sufficient stiffness to equally balanceand counteract the bending of the motor 334 as the motor 334 is expanded(e.g., as shown in FIG. 23) and contracted (e.g., as shown in FIG. 24).This action is provided at least in part because of the relatively lessamount of material, and therefore less stiffness (e.g., compared toembodiments with stiffeners such as 280 described above). The presenceand configuration (e.g., shape, elastic modulus, alignment with struts356) of the stiffener 380 can be balanced with the mechanics of theflexure 312 to minimize bending of the motor 334 and flexure 312,maximize longitudinal stroke of the motor 334, and/or reverse thebending profile of the motor 334. In one embodiment, the stiffener 380provides a stroke increase of approximately 30% over similar embodimentsof the flexure with no stiffener. Stiffener 380 also provides less twistalong the long axis of the motor 334 during actuation of the motor.Minimizing twist of the motor 334 can reduce excitation of flexureresonance modes by reducing motion of the flexure arms and traces.

Connectors 345 electrically and mechanically connect the motor 334 tothe flexure 312. More specifically, the connectors 345 make electricalconnections between traces of the flexure 312 and terminals of the motor334. The connectors 345 can further attach the motor 334 to the springarms 352. The slider 332 is mounted to a slider mounting of the tongue333. The slider mounting can be a surface of the tongue 333 to which theslider 332 can be attached, such as with an adhesive such as epoxy.Rotation of the tongue 333 by actuation of the motor 334 rotates theslider mounting, and thereby the slider 332, about a tracking axis.

FIG. 25 is detailed isometric view of the stainless steel side of thedistal end of a flexure 412 having a DSA structure 414 with a stiffener480 in accordance with another embodiment of this disclosure. FIG. 26 isa distal end view of the flexure 412 shown in FIG. 25. FIG. 27 is anillustration of the flexure 412 shown in FIG. 25 when the motor 434 isactuated into an expanded state. The flexure 412 is part of a DSAstructure 414 that can be similar to that of DSA structure 214 describedabove or other DSA structure referenced herein except where noted.Features of flexure 412 that are the same or similar to those of otherflexures are indicated by similar reference numbers. As shown, thestiffener 480 has a center section 487 and a pair of opposite sidesections 488 and 489. Each of the side sections 488 and 489 areseparated from the center section 487 by openings 491. Each opening 491is a void in the stiffener 480 that extends from a first side of thestiffener 480 to a second side of the stiffener 480 opposite the firstside. Each opening 491 is entirely bounded along the plane of thestiffener is lateral (i.e. left and right) as well as proximal anddistal directions. Alternatively, an opening 491 can be open on any ofthe lateral, distal, and/or proximal sides.

The stiffener 480 is attached to the motor 434 by a plurality ofadhesive layers 482 ₁-482 ₂. As shown, the plurality of adhesive layers482 ₁-482 ₂ are separate and do not contact one another. Each of theadhesive layers 482 ₁-482 ₂ can be a different type of adhesive suchthat each layer has a different elastic modulus. In the illustratedembodiment, for example, the center section 487 of the stiffener 480 isattached to the motor 434 by a first adhesive 482 ₁ and the sidesections 488 and 489 are attached by a second adhesive 482 ₂. The firstadhesive 482 ₁ can have a relatively low elastic modulus while thesecond adhesive 482 ₂ can have a relatively high elastic modulus suchthat the elastic modulus of the first adhesive 482 ₁ is lower than theelastic modulus of the second adhesive 482 ₂. The first adhesive 482 ₁can, for example, have the same properties as the adhesive 282 describedabove (e.g., by having an elastic modulus of around 100 MPa). The secondadhesive 482 ₂ can, for example, have an elastic modulus of about 2800MPa. Other stiffeners, and other adhesives including adhesives havingother elastic moduli, can be used and are within the scope of thisdisclosure. Since the second adhesive 482 ₂ is generally confined to thelateral sides of the motor 434, the higher elastic modulus of the secondadhesive 482 ₂ resists expansion and contraction over a relativelylimited length. As shown in FIG. 27, the second adhesive 482 ₂, having arelatively high modulus, does not shear to the degree that a relativelylower elastic modulus adhesive would (e.g., as shown in FIG. 20). Thesecond adhesive 482 ₂ remains relatively rigid and can cause an increasein bending of the motor 434 toward the stiffener 480 when the motor 434expands. The amount of stretch from the motor 434 is thereby enhanced,increasing the stroke (e.g., by amounts of 100% or more) over the strokeof similar gimbals without the stiffener 480.

Connectors 445 electrically and mechanically connect the motor 434 tothe flexure 412. More specifically, the connectors 445 make electricalconnections between traces of the flexure 412 and terminals of the motor434. The connectors 445 can further attach the motor 434 to the springarms 452. The slider 432 is mounted to a slider mounting of the tongue433. The slider mounting can be a surface of the tongue 433 to which theslider 432 can be attached, such as with an adhesive such as epoxy.Rotation of the tongue 433 by actuation of the motor 434 rotates theslider mounting, and thereby the slider 432, about a tracking axis.

FIG. 28 is detailed isometric view of the stainless steel side of thedistal end of a flexure 512 having a DSA structure 514 with a stiffener580 mounted on the motor 534. FIG. 29 is a detailed side view of thedistal end of the flexure 512 shown in FIG. 28. The flexure 512 is partof a DSA structure 514 that can be similar to that of DSA structure 214described above or other DSA structure referenced herein except wherenoted. Features of flexure 512 that are the same or similar to those ofother flexures are indicated by similar reference numbers. The stiffener580 is similar to the stiffener 480 described above but the stiffener580 has multiple thicknesses. Specifically, the stiffener 580 hasreduced thickness portions 593 at the distal and proximal ends of thecenter section 587 and opposite side sections 588 and 589. For example,the distal and proximal ends of the stiffener 580 are thinner than themiddle of the stiffener 580. In this way, the reduced thickness portions593 extend along a perimeter of the stiffener 580. As shown, thesections of the stiffener 580 that bridge between the center section 587and the side sections 588 and 589 have a smaller thickness with respectto the respective middles of the center section 587 and the sidesections 588 and 589. Multiple adhesives 582 ₁ and 582 ₂ are attached tothe motor 534 and the stiffener 580. The adhesives 582 ₁ and 582 ₂ canbe the same as or similar to the adhesives 482 ₁ and 482 ₂ describedabove. The adhesive 582 ₁ is underneath the center section 587 and canhave a lower elastic modulus than the adhesives 582 ₂ that areunderneath the side sections 588 and 589. Other embodiments (not shown)can have more than two sections each a having a different thickness(e.g., three sections having different thicknesses) and/or otherconfigurations of different thicknesses.

Connectors 545 electrically and mechanically connect the motor 534 tothe flexure 512. More specifically, the connectors 545 make electricalconnections between traces of the flexure 512 and terminals of the motor534. The connectors 545 can further attach the motor 534 to the springarms 552. The slider 532 is mounted to a slider mounting of the tongue533. The slider mounting can be a surface of the tongue 533 to which theslider 532 can be attached, such as with an adhesive such as epoxy.Rotation of the tongue 533 by actuation of the motor 534 rotates theslider mounting, and thereby the slider 532, about a tracking axis.

FIG. 30 is detailed isometric view of the stainless steel side of thedistal end of a flexure 612 having a DSA structure 614 with anasymmetric stiffener 680 attached to the motor 634 with multipleadhesives 682 ₁ and 682 ₂. The flexure 612 is part of a DSA structure614 that can be similar to that of DSA structure 214 described above orother DSA structure referenced herein except where noted. Features offlexure 612 that are the same or similar to those of other flexures areindicated by similar reference numbers. As shown, each side section 688and 689 of the stiffener 680 forms an “L” shape arm which includes aconnecting section 693 that extends laterally from the center section687 and a longitudinal section 694 that extends longitudinally (e.g.,proximally or distally) from the end of the connecting section 693. Asshown, the connecting sections 693 extend orthogonal with respect to thecenter section 687 and the longitudinal sections 694. Only a singleconnecting section 693 of the stiffener 680 extend between the centersection 687 and each longitudinal section 694. As shown, a first one ofthe connecting sections 693 is proximal with respect to a second one ofthe connecting sections 693. The offset relationship of the connectingsections 693 can mirror the offset relationship of the struts 656. It isnoted that while strut 656 is shown in FIG. 30, the configuration of thestruts 656 can be the same as the struts 56 shown in FIG. 4B. Forexample, a first strut 656 on the right side of the flexure 612 can beproximal of the second strut 656 on the left side of the flexure 612while a first one of the connecting sections 693 on the right side ofthe stiffener 680 is proximal of a second one of the connecting sections693 on the left side of the stiffener 680. The stiffener 680 can bebetween the struts 656 (e.g., from a plan view perspective or along aplane that is coplanar with the flexure 612). The offset profile of theconnecting sections 693 corresponding to the offset profile of thestruts 656 allows the connecting sections 693 to respectivelymechanically counteract the struts 656. The asymmetric configuration ofthe stiffener 680 can reduce twist of the motor 634 during expansion andcontraction. Portions of center section 687 and longitudinal sections694, and connecting sections 693, extend beyond the distal and proximaledges of the motor 634 in the illustrated embodiment. In various otherembodiments (not shown) the stiffener 680 entirely overlays the topsurface of the motor 634 and extends beyond the distal and/or proximaledges of the motor 634. In still other embodiments (not shown) thestiffener 680 has still other shapes and sizes with respect to the shapeand size of the motor 634.

Connectors 645 electrically and mechanically connect the motor 634 tothe flexure 612. More specifically, the connectors 645 make electricalconnections between traces of the flexure 612 and terminals of the motor634. The connectors 645 can further attach the motor 634 to the springarms 652. The slider 632 is mounted to a slider mounting of the tongue633. The slider mounting can be a surface of the tongue 633 to which theslider 632 can be attached, such as with an adhesive such as epoxy.Rotation of the tongue 633 by actuation of the motor 634 rotates theslider mounting, and thereby the slider 632, about a tracking axis.

FIG. 31 is an illustration of a flexure 712 having a DSA structure 714with an asymmetric stiffener 780 in accordance with another embodimentof this disclosure. The flexure 712 is part of a DSA structure 714 thatcan be similar to that of DSA structure 214 described above or other DSAstructure referenced herein except where noted. Features of flexure 712that are the same or similar to those of other flexures are indicated bysimilar reference numbers. As shown, the stiffener 780 has a centersection 787 and oppositely extending first arm 788 and second arm 789.The first arm 788 on one side of the stiffener 780 has a smaller width(i.e., in a direction of the longitudinal axis of the flexure 712) thanthe width of the second arm 789 on the other side of the stiffener 780.The first arm 788 can have a width of about one-half the width of thesecond arm 789. It will be understood that the relative widths of thefirst and second arms 788 and 789 can be reversed such that second arm789 can have a smaller width than the first arm 788. Similar embodimentscan have other relative dimensions. Alternatively, the first and secondarms 788 and 789 can have the same widths. It is also noted that thefirst arm 788 is proximal with respect to the second arm 789. Theasymmetry of the stiffener 780 enables the DSA structure 714 to havedifferent bending characteristics on its opposite transverse sides(i.e., with respect to a longitudinal axis). The offset relationship ofthe first and second arms 788 and 789 can mirror the offset relationshipof the struts 756. It is noted that while strut 756 is shown in FIGS.31-32C, the configuration of the struts 756 can be the same as thestruts 56 shown in FIG. 4B. For example, a first strut 756 on the rightside of the flexure 712 can be proximal of the second strut 756 on theleft side of the flexure 712 while a first arm 788 on the right side ofthe stiffener 780 is proximal of a second arm 789 on the left side ofthe stiffener 780. The stiffener 780 can be between the struts 756(e.g., from a plan view perspective or along a plane that is coplanarwith the flexure 712). The offset profile of the first and second arms788 and 789 corresponding to the offset profile of the struts 756 allowsthe first and second arms 788 and 789 to respectively mechanicallycounteract the struts 756.

FIGS. 32A and 32B are illustrations of the flexure 712 shown in FIG. 31when the motor 734 is actuated into contracted and expanded states,respectively. As shown, because of the relatively lower stiffnessprovided by the first arm 788 due to the second arm 789 being wider, theside of the flexure 712 with the first arm 788 bends more than the sideof the flexure 712 with the second arm 789. The amount of side-to-sidedifferential bending is related to the difference in stiffness betweenthe first and second arms 788 and 789. The rotational center of the DSAstructure 724 can be changed and tuned by the stiffener 780 by adjustingvarious variables, including the relative widths or thicknesses, andtherefore the relative stiffnesses, of the first and second arms 788 and789.

Connectors 745 electrically and mechanically connect the motor 734 tothe flexure 712. More specifically, the connectors 745 make electricalconnections between traces of the flexure 712 and terminals of the motor734. The connectors 745 can further attach the motor 734 to the springarms 752. The slider 732 is mounted to a slider mounting of the tongue733. The slider mounting can be a surface of the tongue 733 to which theslider 732 can be attached, such as with an adhesive such as epoxy.Rotation of the tongue 733 by actuation of the motor 734 rotates theslider mounting, and thereby the slider 732, about a tracking axis.

Flexures with DSA structures having stiffeners can provide importantadvantages. The stiffener changes the deformed shape of the PZT motorwhen the motor expands and contracts during operation. This shape changecan be tailored to increase the stroke amount of the actuator assembly,therefore achieving more stroke for the same input voltage to the motor.Alternatively, the same stroke can be maintained but with a lowervoltage as compared to embodiments without a stiffener. Anotheradvantage of the stiffener is that twist or asymmetric bending of themotor can be minimized by design of the stiffener. Increasing strokeperformance is an advantage in particular for co-located dual stageactuators since high stroke is difficult to achieve due to the inherentlow mechanical advantage when the motor is located close to the sliderthat the motor is moving. Due to low stroke, gimbal actuator designs mayrequire the use of more expensive multi-layer PZT motors as opposed tosimple single layer and lower cost motors. By increasing the strokeperformance, stiffeners can reduce the number of PZT motor layers neededfor a design and even allow for the use of single layer PZT motors toachieve stroke targets.

In some embodiments, the center of rotation of the motor, tongue, and/orslider can be adjusted by tailoring how the motor bends during actuationwith a stiffener. For example, the center of rotation can be located toextend through the dimple load point (e.g., where the dimple contactsthe stiffener). If the actuator's center of rotation is not locateddirectly at the dimple load point, then resonance performance may bereduced. The tailored stiffener designs, discussed above, can be used tomove the center of rotation by changing how the motor deforms.

The stiffener also provides a protective covering over the motor, whichmay otherwise be fragile. For example, the stiffener provides a pointupon which the dimple can press, wherein equivalent pressure from thedimple directly on the motor may damage the motor. The stiffener canprotect the motor surface from mechanical wear due to the dimple andshock loads at the dimple point. Shock loads will be distributed by thestiffener. The stiffener can also provide electrical insulation of themotor. For example, the loadbeam can serve as an electrical ground insome embodiments, and in such case the motor can be insulated fromelectrical connection through the dimple of the loadbeam by thestiffener. If the stiffener is formed from an electrically conductivemetal, then the adhesive layer between the stiffener and the motor canserve as electrical insulation.

While the use of a stiffener has been described in association withvarious gimbaled flexure embodiments, it is noted that a stiffener canbe used with any flexure referenced herein. For example, in theembodiment of FIG. 9-16C ₂, a stiffener can be positioned on the motor134 while the slider 132 can be attached to the stiffener (e.g., with anepoxy adhesive) and/or the slider 132 can be attached to the motor 134at a location not covered by the stiffener.

Although the present invention has been described with reference topreferred embodiments, those skilled in the art will recognize thatchanges can be made in form and detail without departing from the spiritand scope of the invention. For example, although described inconnection with certain co-located DSA structures, stiffeners andassociated features described herein can be used in connection withmotors on other DSA structures, including other co-located DSAstructures.

The following is claimed:
 1. A gimbaled flexure having a dual stageactuation structure, comprising: flexure comprising a gimbal, the gimbalcomprising at least one spring arm and a tongue connected to the atleast one spring arm; a motor mounted on the gimbal, the motorcomprising a top side and a bottom side opposite the top side, thebottom side of the motor facing the flexure; and a stiffener mounted onthe top side of the motor.
 2. The flexure of claim 1, wherein thestiffener is stiffer than a portion of the gimbal and the motor ismounted on the portion of the gimbal.
 3. The flexure of claim 1, whereinthe stiffener limits the degree of bending of the motor duringactivation of the motor.
 4. The flexure of claim 1, wherein the motorbends in a first direction when the motor is activated to expand and themotor bends in a second direction, opposite the first direction, whenthe motor is activated to contract.
 5. The flexure of claim 4, whereinthe presence of the stiffener affects the direction of bending of themotor such that, in absence of the stiffener, the motor bends in thesecond direction when the motor is activated to expand and the motorbends in the first direction when the motor is activated to contract. 6.The flexure of claim 1, wherein the stiffener limits the degree oftwisting of the motor about the longitudinal axis of the motor.
 7. Theflexure of claim 1, wherein the motor twists in a first direction aboutthe longitudinal axis of the motor when the motor is activated to expandand the motor twists in a second direction, opposite the firstdirection, when the motor is activated to contract, and wherein thepresence of the stiffener affects the direction of twist of the motorsuch that, in absence of the stiffener, the motor twists in the seconddirection when the motor is activated to expand and the motor twists inthe first direction when the motor is activated to contract.
 8. Theflexure of claim 1, wherein the stiffener comprises a layer of metal. 9.The flexure of claim 1, wherein the stiffener comprises a layer ofpolymer.
 10. The flexure of claim 1, wherein the stiffener is bonded tothe motor by a layer of adhesive that is between the motor and thestiffener.
 11. The flexure of claim 10, wherein the layer of adhesivehas an elastic modulus of about 100 MPa.
 12. The flexure of claim 10,wherein the layer of adhesive has an elastic modulus that is about 2000times lower than the elastic modulus of the stiffener.
 13. The flexureof claim 1, wherein the stiffener is bonded to the motor by a pluralityof adhesive layers, each adhesive layer of the plurality of adhesivelayers is formed from a different type of adhesive.
 14. The flexure ofclaim 13, wherein each adhesive layer of the plurality of adhesivelayers has a different elastic modulus.
 15. The flexure of claim 13,wherein the stiffener has a center section, a first side section, and asecond side section opposite the first side section, wherein a firsttype of adhesive is disposed underneath the center section but notunderneath the first side section and the second side section, andwherein a second type of adhesive is disposed underneath the first sidesection and the second side section but not underneath the centersection.
 16. The flexure of claim 15, wherein the first type of adhesivehas a lower elastic modulus than the second type of adhesive.
 17. Theflexure of claim 1, wherein the stiffener has a first thickness along afirst portion of the stiffener and a second thickness along a secondportion of the stiffener, the second thickness less than the firstthickness.
 18. The flexure of claim 17, wherein the second portion ispositioned and configured to make contact with a load point dimple. 19.The flexure of claim 17, wherein the second portion is located along aperimeter of the stiffener.
 20. The flexure of claim 1, wherein thestiffener comprises one or more voids in the stiffener, each voidextending from a first side of the stiffener to a second side of thestiffener opposite the first side.
 21. The flexure of claim 1, whereinthe stiffener comprises a left lateral side and a right lateral side,the left lateral side and the right lateral side divided by a midlinealong the center of the stiffener, wherein the left lateral side isasymmetric with respect to the right lateral side.
 22. The flexure ofclaim 1, wherein the stiffener comprises a center section, a first armextending laterally away from the center section in a first direction,and a second arm extending laterally away from the center section in asecond direction.
 23. The flexure of claim 22, wherein the width of thefirst arm is greater than the width of the second arm.
 24. The flexureof claim 22, wherein the first arm extends along a first longitudinalaxis, the second arm extends along a second longitudinal axis, and thefirst arm is offset proximally with respect to the second arm.
 25. Theflexure of claim 1, wherein: the gimbal further comprises a pair ofstruts, the at least one spring arm comprises a pair of spring arms, thetongue is located between the pair of spring arms and is connected tothe pair of spring arms by the pair of struts, the motor is mounted onthe pair of spring arms, the tongue comprises a slider mounting, andelectrical activation of the motor bends the pair of struts to move theslider mounting about a tracking axis.
 26. The flexure of claim 1,wherein: the at least one spring arm comprises a pair of spring arms,the tongue is located between the pair of spring arms and is connectedto the pair of spring arms, the gimbal further comprises a pair ofstruts respectively connected to the tongue, the gimbal furthercomprises a pair of motor mounting pads respectively connected to thepair of struts, the pair of motor mounting pads remote from the pair ofspring arms, the motor is mounted on the pair of motor mounting pads,either of the motor and the stiffener comprises a slider mounting, andelectrical activation of the motor bends the pair of struts to move theslider mounting about a tracking axis.
 27. A gimbaled flexure having adual stage actuation structure, comprising: flexure comprising a gimbal,the gimbal comprising a pair of spring arms, a pair of struts, and atongue between the spring arms; a motor mounted on the gimbal, the motorcomprising a top side and a bottom side opposite the top side, thebottom side of the motor facing the flexure; a stiffener mounted on thetop side of the motor; at least one layer of adhesive located betweenthe stiffener and the motor and bonded to the stiffener and the motor;and a slider mounting, wherein electrical activation of the motor bendsthe pair of struts to move the slider mounting about a tracking axiswhile the stiffener limits the degree of bending of the motor during theelectrical activation.
 28. The flexure of claim 27, wherein: thestiffener comprises a center section, a first arm extending laterallyaway from the center section along a first longitudinal axis, and asecond arm extending laterally away from the center section along asecond longitudinal axis, and the first arm is offset proximally withrespect to the second arm.
 29. The flexure of claim 27, wherein thestiffener has a center section, a first side section, and a second sidesection opposite the first side section, wherein a first type ofadhesive is disposed underneath the center section and a second type ofadhesive is disposed underneath the first side section and the secondside section.
 30. A gimbaled flexure having a dual stage actuationstructure, comprising: flexure comprising a gimbal, the gimbalcomprising a pair of spring arms, a pair of struts, and a tongue locatedbetween the pair of spring arm and connected to the pair of spring armsby the pair of struts, the tongue comprising a slider mounting; a motormounted on the pair of spring arms, the motor comprising a top side anda bottom side opposite the top side, the bottom side of the motor facingthe flexure; a stiffener mounted on the top side of the motor, thestiffener comprising a left lateral side and a right lateral side thatis asymmetric with respect to the left lateral side; and at least onelayer of adhesive located between the stiffener and the motor and bondedto the stiffener and the motor, wherein electrical activation of themotor bends the pair of struts to move the slider mounting about atracking axis while the stiffener limits the degree of bending of themotor during the electrical activation.